It’s really depends some strings will slide more and work better with concave or curved shapes. I like flats and center tracks but it’s really up to preference. I also haven’t tried any stepped bearings. This topic above was me trying to figure out the facts about bearing shapes bc there was some conflicting info out there.
Bearings don’t matter all that much though like the cheap yye flat 10 balls work really well for me and I usually just use whatever comes in the Yoyo unless it’s concave.
Lots of people that are on here say stepped concave shapes are the best for performance and they’re probably right but I haven’t tried them yet and don’t feel any urgency to try them